The threat by majority Democrats to change Senate rules to make confirmation easier for some nominees could open up two cans of worms that could weaken the chamber’s minority party for years to come.

Exasperated by what he considers excessive Republican efforts to block some of President Barack Obama’s appointments, Senate Majority Leader Harry Reid, D-Nev., is threatening to use his muscle to change the rules so only simple majority votes are needed to approve top-level federal agency jobs.

Currently, opponents can thwart those appointments with filibusters. Since those delaying tactics take three-fifths majorities to end, Reid currently needs the votes of 60 of all 100 senators to push those nominations through his chamber – a high hurdle since Reid generally controls only 54 votes, including two usually loyal independents.

Should Reid prevail, that could encourage Republicans to broaden the exception whenever they recapture the Senate, experts say, perhaps also eliminating the 60-vote margin needed to end filibusters on legislation. Republicans have pointedly said would make it easier to establish a nuclear waste depository at Nevada’s Yucca Mountain, which Reid has thwarted for years.